UPC EETAC Bachelor's Degree in Telecommunications Systems and in Network Engineering EEL

Chapter 2 problems

      - A2.3 -

Analysis of an asynchronous circuit (Circuit_D)

Products

A2.2

A2.4

1. Specifications

Fig. 1 represents the internal circuit of chip 74LS92 containing several chained flip-flops from its datasheet. Let us adapt it as usual to our naming style and conventions.

We can use our set of tools to analyse Circuit_D represented in Fig. 2 built using this chip resources and external logic gates.

Circuit 74LS92

Fig. 1. 74LS92 chip equivalent internal circuit.

Read its datasheet to determine how does it work (what is the funcion of each pin). Some J and K inputs are not driven, let us assume that they are connected to '1'.

Analyse Circuit_D in Fig. 2 using method II: Proteus capture and simulation, or method III: VHDL synthesis and test. Determine how does the circuit work, meaning finding the vector output P(4..1) in a clocked (CLK) timing diagram. 

What is the maximum CLK frequency when picking the PLD target chip indicated below?

 - Cyclone IV

- MAXII

Test your solutions using method I: handwritten analysis.

Circuit_D

Fig. 2. Circuit_D to be analysed using our three methods.